Not Applicable.
Not Applicable.
The present invention relates generally to an apparatus for clamping a vehicle brake rotor having specific dimensions during a manufacturing process whereby the peripheral edges of the brake rotors are milled, and more specifically, to an improved clamping apparatus which is universally adjustable to clamp brake rotors of varying dimensions.
The manufacture of brake rotors for use in automotive vehicle applications begins with a rough casting of a metal brake rotor shown generally at 10 in FIG. 1. This rough casting is machined to provide the smooth friction surfaces 12 against which vehicle brake friction pads will clamp to generate a braking force. Additional machining operations drill suitable bores 14 into the brake rotor 10 through which wheel lugs or retaining bolts are passed to secure the brake rotor to a vehicle wheel assembly. A large diameter central axial bore 16 in the brake rotor is machined for mounting the brake rotor 10 onto a vehicle wheel assembly. Finally, the brake rotor 10 is rotationally balanced by milling or grinding material from the inner surfaces 18 of channel 20 in the peripheral edge of the brake rotor 10 to eliminate any static and dynamic imbalances present as the brake rotor rotates about the central axis Axe2x80x94A. Material is removed by the milling or grinding operation only from the inner surfaces 18 of channel 20 so as to maintain a uniformly circular perimeter on the smooth friction surface 12
Conventional milling or grinding apparatus, such as that sold by Balance Technology, Inc. of Ann Arbor, Mich., secure an individual brake rotor to be balanced using a pair of specifically sized annular clamp rings in combination with matching diameter annular spacer rings. To prevent damage to the brake rotor friction surface during the milling or grinding operations, the brake rotor must be secured by the clamp rings within a predetermined spacing from the peripheral edge of the brake rotor.
To set up a conventional milling or grinding apparatus, a lower clamp ring mounting flange, having an outer diameter suitable for use with the out diameter size of a brake rotor to be machined, is secured to the drive head or spindle of the milling or grinding apparatus. An annular spacer ring of suitable height and diameter is then secured thereto, concentric with the drive head or spindle, and an annular clamp ring having matching diameter is fastened to the annular spacer ring. Next, a centering cone suitably sized to engage the inner surfaces of the brake rotor central axial bore is fitted to a spring-mounted plunger shaft, coaxially disposed along the rotational axis of the drive head or spindle.
An upper clamp ring mounting flange of corresponding outer diameter is next secured to the milling or grinding apparatus, along with an upper annular spacer ring of suitable height and diameter, and an upper annular clamp ring, to form the upper clamping assembly. The entire upper clamping assembly is configured for movement along the rotational axis of apparatus to engage the upper surface of a brake rotor seated on the lower clamping assembly.
A brake rotor placed over the centering cone, supported by the spring plunger. The brake rotor s secured in place by an axial clamping force exerted through the upper clamping assembly, depressing the centering cone and spring plunger, and holding the brake rotor between the upper and lower annular clamp rings, adjacent the rotor peripheral edge. Once clamped in this manner, the brake rotor can be spun rotationally about the central axis to align a milling or grinding location with the milling or grinding head, and held in a secure manner for engagement with the milling or grinding head during removal of material from a peripheral edge.
As can be readily seen by those of ordinary skill in the art, the conventional milling and grinding apparatus for use with vehicle brake rotors is suited for high-volume production runs of identically sized brake rotors. Since the conventional milling and grinding apparatus requires removal and replacement of several clamping components to accommodate brake rotors of differing diameters or differing thickness, resetting of the conventional systems for low-volume or limited production runs of brake rotors having different outer diameters and thickness is a time-consuming process.
Furthermore, it will be appreciated that to accommodate brake rotors of different outer diameters and different thickness, suitable alternate components such as the annular clamp rings, flanges, and annular spacer rings, must be readily available. For example, to machine sixteen different brake rotors of four different diameters and four different thickness, requires four different lower flanges, sixteen different lower annular spacer rings, four different lower clamp rings, four different upper flanges, four different upper annular spacer rings, and four different upper clamp rings, each of which must be removed and replaced to accommodate a differently sized brake rotor.
Accordingly, there is a need in the vehicle brake manufacture industry for a brake rotor milling and grinding apparatus which can be readily reconfigured to accommodate a wide range of brake rotor sizes and thickness, without the need for a complete disassembly and an exchange of numerous components, thereby permitting rapid reconfiguring suitable for low-volume or highly variable brake rotor product lines.
Briefly stated, the present invention provides a brake rotor clamping apparatus suitable for use with a brake rotor milling and grinding apparatus, and which is readily adjustable to a wide range of brake rotors having varied diameters and thickness. The brake rotor clamping apparatus includes a lower clamp pad mounting flange secured to a drive head or spindle on a drive shaft. A plurality of sets of attachment points are disposed in an upper surface of the lower clamp pad mounting flange at varying radial placements. A plurality of clamp pad segments fitted with replaceable spacer elements are secured to the lower clamp pad mounting flange by bolts threaded into one set of attachment points. The specific set of attachment points into which the clamp pad segments are disposed corresponds to the dimensions of the brake rotor to be machined. A centering cone for receiving the brake rotor is secured on a spring plunger concentrically mounted to the drive shaft, and concentric with the lower clamp pad mounting flange. Axially opposing the lower clamp pad mounting flange is an upper clamp pad mounting flange including a second plurality of sets of attachment points disposed at varying diameters. A matching plurality of clamp pad segments fitted with spacer elements are secured to the upper clamp pad mounting flange by bolts threaded into the one set of attachment points. The specific set of attachment points into which the upper clamp pad segments are disposed opposes the set of threaded bores into which the clamp pads on the lower clamp pad mounting flange are mounted, such that a brake rotor seated on the centering cone is clamped between the opposing pairs of clamp pad segments.